I'm not deep into geometry, but one of my favourite web apps / UI designs is the Polyhedra Viewer by Nat Alison [1][2], which shows relations, properties, and transformations in a very natural way.
Tom7's video on polyhedra properties [3] is also great, and taught me about the best Unicode characters (sic) [4]:
︘ U+FE18 Presentation Form For Vertical Right White Lenticular Brakcet
Tom7's video on polyhedra properties [3] is also great, and taught me about the best Unicode characters (sic) [4]:
1. https://polyhedra.tessera.li/2. https://aperiodical.com/2018/09/polyhedra-viewer-meet-nat-al...
3. https://www.youtube.com/watch?v=QH4MviUE0_s
4. https://www.compart.com/en/unicode/U+FE18